Author:

Cui-Zu Chang(The Penn State University & Massachusetts Institute of Technology)

The quantum anomalous Hall (QAH) effect can be considered as the quantum
Hall (QH) effect without external magnetic field, which can be realized by
time reversal symmetry breaking in a topologically non-trivial system [1,
2]. A QAH system carries spin-polarized dissipationless chiral edge
transport channels without the need for external energy input, hence may
have huge impact on future electronic and spintronic device applications for
ultralow-power consumption. The many decades quest for the experimental
realization of QAH phenomenon became a possibility in 2006 with the
discovery of topological insulators (TIs). In 2013, the QAH effect was
observed in thin films of Cr-doped TI for the first time [3]. Two years
later in a near ideal system, V-doped TI, contrary to the negative
prediction from first principle calculations, a high-precision QAH
quantization with more robust magnetization and a perfectly dissipationless
chiral current flow was demonstrated [4]. In this talk, I will introduce the
route to the experimental observation of the QAH effect in above-mentioned
two systems [3, 4], and discuss the zero magnetic field dissipationless edge
current flow as well as the origin of the dissipative channels in the QAH
state [5]. Finally I will talk about our recent progress on the QAH
insulator-Anderson insulator quantum phase transition and its scaling
behaviors [6].
References
[1] F. D. M. Haldane, Phys. Rev. Lett. 61, 2015-2018 (1988).
[2] R. Yu et al, Science 329, 61-64 (2010).
[3] Cui-Zu Chang et al, Science 340, 167(2013).
[4] Cui-Zu Chang et al, Nature Materials 14, 473(2015).
[5] Cui-Zu Chang et al, Physics Review Letters 115, 057206 (2015).
[6] Cui-Zu Chang et al, Physics Review Letters 117, 126802 (2016)..

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2017.MAR.F23.1